Combination lock



FIG. 1 is a front view of a combination lock showing my new design;

FIG. 2 is a rear view thereof;

FIG. 3 is a plan view thereof;

FIG. 4 is a bottom view thereof;

FIG. 5 is a right end view thereof;

FIG. 6 is a left end view thereof;

FIG. 7 is an exploded perspective view thereof. 

The ornamental design for a combination lock, as shown and described. 